Method for controlling a power-shift multi-speed boat transmission

ABSTRACT

According to the method for controlling at least one power-shift multi-speed boat transmission in conjunction with a fixed propeller or water jet, the upshift speed is a function of a value which indicates the intended acceleration, especially a function of the regulating speed of the control lever or the speed of modification of the transmission input speed.

FIELD OF THE INVENTION

The invention concerns a method for controlling a power-shift,multi-speed boat transmission.

BACKGROUND OF THE INVENTION

Multi-speed boat transmission, combined with a fixed propeller or waterjet, are know already. Such transmissions allow a variable adaptation ofthe motor to different operating conditions whereby the motor can alwayswork at the optimum rotational speed range.

DE 196 24 913 A1 discloses a marine transmission system having onemotor, one shifting mechanism and one programmable electronic controldevice with a shift parameter matrix. The electronic control devicemonitors the motor load and the rate of revolutions and produces acontrol signal which controls the shifting operations.

DE 19 49 938 has made known a shifting automatic system for a boattransmission system having one-step or multi-step transmissions whereina first control loop adjusts, via the torque of the boat propeller, theoutput rotational speed of the transmission required by the drivingconditions that occur and a second control loop controls the rotationalspeed of the motor and the output of the motor in accordance with thefirst control loop.

The above cited prior art requires coordination of the transmission withthe electronic system of the motor. Consequently, it is not possible tocombine different types of transmission with different motors withouthigh expenditure in adaptation and costs.

SUMMARY OF THE INVENTION

The invention is based on the problem of making available a method forcontrol of a power-shift, multi-speed transmission which automaticallypermits a variable adaptation to different operating conditions withoutrequiring a coordination of the transmission with the electronic systemof the motor.

Thereby the inventive method can be universally utilizable.

In addition, the change of gear must occur without tractioninterruption. This is of great importance, particularly in fast boats,in order that during the gearshift operation the boat does not fall offthe plane with its low resistance to the motion.

Accordingly, it is proposed to deduce the intended acceleration from themovement of the control lever or from the change of the input rotationalspeed of the transmission and thus to introduce a shifting operation atdifferent rotational speeds of the motor.

Consequently, a quick movement of the control lever or a quick upshiftof the motor is interpreted as a desire for high acceleration for theboat and the shift point in the higher gear is moved toward high motorrotational speeds. In such a case, the rotational speed of the motor atthe shift point can amount to 95% of the nominal rotational speed andpreferably be in the interval between 80% and 100% of the nominalrotational speed.

On the other hand, a slow movement of the control lever or a slowupshift of the motor is interpreted as a desire for a more moderateacceleration of the boat and the shift point in the high gear is movedtoward low rotational speeds of the motor. A typical value of therotational speed of the motor at the shift point is 75% of the nominalrotational speed. Other values for the rotational speed of the motor atthe shift point can be in the interval between 60% and 80% of thenominal rotational speed value.

According to the invention, the upshift is introduced only when theforward gear is engaged. For reasons of safety, the quick gear cannot beengaged in reverse motion.

According to the invention, the possibility of a kick-down downshift isprovided for when it should be accelerated at a rotational speed rangeabove the rotational speed of the downshift.

In boats equipped with a multi-engine installation, the shiftingoperation occurs simultaneously in all transmissions as soon as atransmission meets the shifting criterion.

The rotational speed of the motor can be optionally lowered during thegear shift.

This described method also provides for the possibility of a manual gearshift. However, to prevent damage to the power transmission due tooperating error, the rotational speed range for manual gear shift islimited, a typical value of the nominal rotational speed being 45% here.At high rotational speeds of the motor, the introduced gear position isblocked.

The inventive control method has the advantage that an expensivecoordination with the electronic system of the motor is not required.Thus, several types of transmissions can be combined with severalmotors.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in detail herebelow with reference to asingle FIGURE which shows a diagram illustrating the interrelationbetween the regulating speed of the control lever and the upshiftrotational speed, the same as the downshift rotational speed of themotor, within the scope of the inventive method.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Although, as shown here, the interrelation is linear, it is alsopossible according to the invention to take as basis anotherinterrelation of the two variable regulating speed and upshiftrotational speed. Other values can also be implemented for introducingthe shifting operations.

Consequently, when the boat speed is returned the high gear remainsengaged until this downshift rotational speed; only when falling belowthe rotational speed is the lower gear down changed.

The interrelation between modification of speed of the transmissioninput rotational speed and the upshift rotational speed can also beillustrated with reference to this diagram, since a direct interrelationexists between the modification of the rotational speed of thetransmission and the regulating speed of the control lever: the quickerthe control lever is moved, the quicker the rotational speed of themotor is increased.

What is claimed is:
 1. A method for control of at least one power-shift,multi-speed boat transmission combined with a fixed propeller or waterjet having a control lever for regulating a rotational speed of thetransmission, the method comprising the step of controlling therotational speed at which an upshift of the transmission occurs as adirect function of a regulating speed of the control lever.
 2. Themethod according to claim 1, further comprising the step of moving thetransmission into a high gear toward a high rotational speed of a motorwhen a high regulating speed of the control lever is interpreted as ademand for a highest acceleration of the boat.
 3. The method accordingto claim 2, further comprising the step of using an interval of between80% and 100% of a nominal rotational speed as a shift point rotationalspeed of the motor.
 4. The method according to claim 1, furthercomprising the step of moving the shift point in the high gear toward alow rotational speed of the motor when a low regulating speed of thecontrol lever is interpreted as a demand for a moderate speed of theboat.
 5. The method according to claim 4, further comprising the step ofusing an interval of between 60% and 80% of a nominal rotational speedas a shift point rotational speed of the motor.
 6. The method accordingto claim 1, further comprising the step of allowing an upshifting onlywhen a forward gear is engaged.
 7. The method according to claim 1,further comprising the step of preventing upshifting when in a reversedrive.
 8. The method according to claim 1, further comprising the stepof engaging a low gear when the control of the transmission fails. 9.The method according to claim 1, further comprising the step ofmaintaining a high gear until the rotational speed of the motor fallsbelow a downshift rotational speed and then automatically downshiftingthe transmission.
 10. The method according to claim 9, furthercomprising the step of providing a downshift rotational speed intervalof between 35% and 70% of a nominal rotational speed of the motor. 11.The method according to claim 1, further comprising the step ofproviding for a kick-down downshift when acceleration is to be effectedin a rotational speed range above the downshift rotational speed. 12.The method according to claim 1, further comprising the step ofproviding a boat with a plurality of power-shift, multi-speed boattransmission with each transmission driving a fixed propeller or waterjet, and operating gearshifts simultaneously as soon as one of thetransmissions meets a shifting criterion.
 13. The method according toclaim 1, further comprising the step of lowering, during the shiftingoperation, the rotational speed of the motor.
 14. The method accordingto claim 1, further comprising the step of providing a manual gearshiftin which, in order to avoid damage to the transmission due to operatorerror, the rotational speed range for manual gearshifting is limited.15. The method according to claim 14, further comprising the step oflimiting the rotational speed range for manual gearshifting to a valuebetween 35% and 60% of a nominal rotational speed.
 16. A method forcontrol of at least one power-shift, multi-speed boat transmissioncombined with a fixed propeller or water jet having a control lever forregulating a rotational speed of the transmission, the method comprisingthe step of controlling the rotational speed at which an upshift of thetransmission occurs as a function of a gradient of a transmission inputrotational speed.
 17. The method according to claim 16, furthercomprising the step of moving the transmission into a high gear toward ahigh rotational speed of a motor when a quick increase of a transmissioninput rotational speed is interpreted as a demand for a highestacceleration of the boat.
 18. The method according to claim 17, furthercomprising the step of using an interval of between 80% and 100% of anominal rotational speed as a shift point rotational speed of the motor.19. The method according to claim 16, further comprising the step ofmoving the shift point in the high gear toward a low rotational speed ofthe motor when a slow increase of the rotational speed of thetransmission is interpreted as a demand for a moderate speed of theboat.
 20. The method according to claim 19, further comprising the stepof using an interval of between 60% and 80% of a nominal rotationalspeed as a shift point rotational speed of the motor.
 21. The methodaccording to claim 16, further comprising the step of allowing anupshifting only when a forward gear is engaged.
 22. The method accordingto claim 16, further comprising the step of preventing upshifting whenin a reverse drive.
 23. The method according to claim 16, furthercomprising the step of engaging a low gear when the control of thetransmission fails.
 24. The method according to claim 16, furthercomprising the step of maintaining a high gear until the rotationalspeed of the motor falls below a downshift rotational speed and thenautomatically downshifting the transmission.
 25. The method according toclaim 24, further comprising the step of providing a downshiftrotational speed interval of between 35% and 70% of a nominal rotationalspeed of the motor.
 26. The method according to claim 16, furthercomprising the step of providing for a kick-down downshift whenacceleration is to be effected in a rotational speed range above thedownshift rotational speed.
 27. The method according to claim 16,further comprising the step of providing a boat with a plurality ofpower-shift, multi-speed boat transmission with each transmissiondriving a fixed propeller or water jet, and operating gearshiftssimultaneously as soon as one of the transmissions meets a shiftingcriterion.
 28. The method according to claim 16, further comprising thestep of lowering, during the shifting operation, the rotational speed ofthe motor.
 29. The method according to claim 16, further comprising thestep of providing a manual gearshift in which, in order to avoid damageto the transmission due to operator error, the rotational speed rangefor manual gearshift is limited.
 30. The method according to claim 29,further comprising the step of limiting the rotational speed range formanual gearshift to a value between 35% and 60% of a nominal rotationalspeed.